1. Field of the Invention
The present invention relates to a metal catalyst, and in particular relates to a highly dispersed metal catalyst and method for manufacturing the same.
2. Description of the Related Art
For a fuel cell, the critical technology is the catalyst for transforming chemical energy to electrical energy. Generally, the catalyst is platinum. For achieving sufficient current density, high content platinum is necessary, thereby increasing cost of production. Alternatively, the platinum may be supported on an active carbon with high surface area to achieve better utilization ratio. Presently, the supported platinum catalyst is synthesized as follows: first, the carbon support is modified; second, the platinum metal precursor is reduced by a reductant; and third, the platinum metal is deposited on the modified carbon support. Because the carbon support is easily aggregated, the surface between the aggregated carbon support cannot be utilized, such that the platinum metal is not evenly dispersed and aggregated. Therefore, a highly loaded and evenly dispersed platinum catalyst is difficult to achieve employing aggregated carbon supports. In manufacturing membrane electrode assemblies (MEA), the catalyst should be prepared as slurry prior to MEA fabrication. Even if the carbon support is modified, the catalyst in the step of slurry preparation will aggregate to larger particles without well dispersion. Consequently, catalyst activity is reduced after forming the MEA.
Accordingly, a novel catalyst is called for, for solving the described problem such as aggregation of the support, e.g. carbon black.